The clinical utility of measuring the macular outer retinal thickness in patients with glaucoma

Few optical coherence tomography (OCT) studies have investigated outer retinal thickness including the photoreceptor layer in glaucoma. We measured changes in the macular outer retinal thicknesses using OCT in patients with glaucoma with an average follow-up of 2.9 ± 0.8 years.

A total of 39 eyes of 39 patients with primary open-angle glaucoma were analyzed. The RTVue-100 was used to measure the macular outer retinal, macular ganglion cell complex, and circumpapillary retinal nerve fiber layer thicknesses, global loss volume, and focal loss volume. Using the paired t test, baseline parameters were compared with those at the last follow-up.

The average baseline mean deviation value in the Humphrey Field Analyzer was -2.13 dB. The ganglion cell complex thickness significantly decreased over the follow-up period (baseline thickness, 79.66 ± 7.71 μm; final thickness, 76.79 ± 7.39 μm; p<0.001). There were significant differences between baseline and final visit measurements for circumpapillary retinal nerve fiber layer thickness, global loss volume, and focal loss volume (p<0.001, p<0.001, and p = 0.004, respectively). However, there was no significant change in outer retinal thickness (baseline thickness, 167.56 ± 7.26 μm; final thickness, 167.25 ± 7.93 μm; p = 0.540).

Outer retinal thickness was not altered during the follow-up period. The stability of outer retinal thickness may indicate the reliability of OCT analysis for glaucoma follow-up.